“If you want to set it so high that no big bank ever goes bankrupt… I think that would greatly diminish growth,” he told a US Chamber of Commerceconference.

Too large a disparity in capital requirements between Europe and the US would mean “you’re pretty much putting the nail in our coffin for big American banks,” he said.

Urging regulators to make a quick decision, he said the uncertainty meant banks were already restricting their lending, nervous of the “anger and the shrillness – and Switzerland says it’s got to be 19 percent and people in the UK say it’s got to be 15 percent.”

Spencer Bachus, the Republican chairman of the House financial services committee, has said that regulators are there to “serve” the banks and warned the Treasury not to hurt Goldman Sachs’ // [GS 159.37 0.30 (+0.19%) ]// shareholders when it writes new rules implementing Dodd-Frank. Restrictions on debit card fees charged to retailers are also coming under attack in Congress.

John Tester, Democratic senator from Montana, has closed in on the 60 votes he needs to overturn the rule. He was supported on Wednesday by Mr. Dimon who called it “basic price fixing at its worst”.

“It basically penalizes us for having debit cards,” he said. “I think it was very unfairly done in the middle of the night with no facts and analysis whatsoever. This is not the way legislation should be done.”

He said the new law had failed to improve the regulatory architecture. “We had a system of too many regulators, too much overlap and too many gaps. Instead of simplifying and strengthening, we added more. It’s even more complicated now.”

Separately, Mr. Dimon said that he did not expect a rash of defaults of municipality debt but did say that “maybe 100” could default. “It’s not going to shatter America,” he said.